diff --git a/src/common/States.jl b/src/common/States.jl
index 92c499b8..ec02ed4f 100644
--- a/src/common/States.jl
+++ b/src/common/States.jl
@@ -209,6 +209,10 @@ Base.setindex!(s::State, v, n, ::Type{Val{:v}}) = begin
     u = s[n, :u]
     s[n, :u] = v.*u./abs.(u)
 end
+Base.setindex!(s::State, v, n, ::Type{Val{:φ}}) = begin
+    u = s[n, :u]
+    s[n, :u] = abs.(u).*exp.(im.*v)
+end
 Base.setindex!(s::State, v, n, ::Type{Val{:var}}, i) = begin
     s[internalindex(s, n, i)] = v
 end
diff --git a/test/common/States.jl b/test/common/States.jl
index a757825c..faf1a17f 100644
--- a/test/common/States.jl
+++ b/test/common/States.jl
@@ -180,6 +180,17 @@ s_2 =  state_from_dict["bus2", :u] * conj(i_2)
 @test state_from_dict[:, :p] ==  real(state[:, :u] .* conj.([i_1, i_2, i_3]))
 @test state_from_dict[:, :q] ==  imag(state[:, :u] .* conj.([i_1, i_2, i_3]))
 
+# exchange phi
+state[2, :φ] = φ_Sw2
+@test state[2:3, :φ] ≈ [φ_Sw2, φ_Sw2]
+state[2:3, :φ] = [φ_Sw1, φ_Sw2]
+@test state[2:3, :φ] ≈ [φ_Sw1, φ_Sw2]
+
+state_from_dict["bus2", :φ] = φ_Sw2
+@test state_from_dict[["bus2","bus3"], :φ] ≈ [φ_Sw2, φ_Sw2]
+state_from_dict[["bus2","bus3"], :φ] = [φ_Sw1, φ_Sw2]
+@test state_from_dict[["bus2","bus3"], :φ] ≈ [φ_Sw1, φ_Sw2]
+
 ## binary operations ##
 s1 = State(grid, ones(systemsize(grid)))
 s2 = State(grid, ones(systemsize(grid)))